This invention relates to aerial decoy arrangements for the protection of potential targets (e.g. ships) against radar-controlled or heat-seeking missiles.
In the case of radar decoy arrangements, chaff-dispensing rockets may be used to dispense their chaff pay-loads at a predetermined time interval after rocket launch to provide an appropriately positioned aerial chaff cloud which is capable of producing a radar echo comparable to the potential target.
For the decoy of heat-seeking missiles, rockets or mortars may be used to provide at predetermined time intervals after launch an aerial infra-red display pattern intended to divert an approaching missile away from a potential target and towards the infra-red display. The infra-red mortar decoy arrangement may utilize multi-mortar packs the mortars of which are arranged to be fired in rapid succession to produce a progressively developing infra-red display pattern.
In the aforesaid decoy arrangements, the chaff or infra-red rockets or mortars, as the case may be, may be arranged to be launched from the barrels of a multi-barrel launcher in response to the application of firing pulses to an inductive coupling arrangement having the respective parts thereof (i.e. primary and secondary) embodied in the base of the launcher barrel and the rear end of the chaff-filled or infra-red rocket or mortar (multi-mortar pack).
In the case of mortars, it may be arranged that a pyrotechnic fuse ignited at launch of the mortar causes the mortar pay-load (e.g. infra-red) to be discharged or dispensed after a predetermined time interval from launch dependent upon the "fuse time". Alternatively, the mortar may embody a simple battery-powered electric timing circuit which may be pre-set to provide an electrical output for initiating the dispensing of the mortar pay-load at an appropriate time interval following launch.
However, in the case of chaff-dispensing rockets, it may be arranged that the rocket embodies power storage means and a variable timing circuit arrangement. The power storage means may comprise capacitor means which is arranged to be charged in response to a charging pulse of relatively high frequency applied to the inductive coupling prior to the application of the previously mentioned firing pulse. The power stored in the capacitor means is utilized to render the variable timing circuit arrangement effective to respond to the previously mentioned timing pulses which will be of the same frequency as the charging pulse and which are also applied to the rocket through the inductive coupling. These timing pulses operate a counter for pre-setting the time interval between launch of the rocket and the initiation of the chaff-dispensing operation. The stored power produces a count down operation in the timing circuit consequent upon the launch of the rocket and also powers the initiation of the chaff-dispensing operation.
In order to monitor the firing and launching of the rockets or mortars from the launcher barrels, each of the barrels which are usually conveniently arranged in groups of three may be provided with switches the conditions of which indicate the unloaded or loaded condition of the appertaining barrels and also serve to indicate the launch of each mortar of a multi-mortar pack. The inductive coupling primaries of the barrels of each group may be supplied with pulses (e.g. firing, charge and timing pulses) and the barrels monitored through a selector switch which may be controlled to step from one barrel to another as required.
The firing pulses and, where appropriate, the charge and timing pulses, for each group of barrels may be derived from an oscillator module appertaining to the group of barrels in response to data fed from a launcher control module which also monitors the operation of the launcher barrels as status information is fed back thereto.
For the purpose of monitoring the launcher control module control outputs without the necessity of actually providing launcher barrels and oscillator modules and without actually loading the barrels with rockets or mortars and firing the latter, the present invention provides a launching barrel/oscillator module simulation unit.